In a reflector antenna[?], the relative reduction in the effective aperture of the antenna caused by the masking effect of other antenna parts, such as a feed horn or a secondary reflector, which parts obstruct the radiation path.
... of age or older. The median age is 44 years. For every 100 females there are 99.5 males. For every 100 females age 18 and over, there are 88.8 males.
The median income ...